All mammals, and in particular humans, can suffer from dryness on particular areas of the body. The skin and mucosal membranes of the body are most often affected. With respect to mucosal membranes, the dryness is the result of the generation of an insufficient quantity of mucoproteins and mucopolysaccharides on the affected area to hold fluid in contact with the cells. When insufficient moisture is present, the mucoproteins and mucopolysaccharides cannot create a sufficient barrier to irritation and infection. Accordingly, the affected individual is subjected to a higher degree of local infections with respect to the affected area, and such local infections can spread systemically. When such a systemic infection results, the consequences can be quite serious. Accordingly, it is important not only to relieve dryness in affected areas, but also to prevent the initial formation of dryness and therefore prevent the initial infections. Because the respiratory (upper and lower tracts) and gastrointestinal tracts are exposed to large amounts of foreign material, including bacteria and viruses, it is particularly important to maintain intact mucosal membranes in these areas.
A number of different compositions and methods for treating various types of dryness are described within the literature. For example, U.S. Pat. No. 4,232,003, issued Nov. 4, 1980, to Posthuma et al., discloses a composition referred to as a synthetic physiological mucous which is indicated as having particular usefulness in connection in treating the dryness of vaginal tissues and as a surgical lubricant. The composition is a pituitous aqueous solution of a high molecular polyacrylamide. Such synthetic mucous compositions and methods for using such compositions to treat dryness are also disclosed within U.S. Pat. No. 3,965,906, issued Jun. 29, 1976.
The general concept of imparting lubricicity to a substrate such as skin, hair or mucous membranes is discussed within U.S. Pat. No. 4,128,631, issued Dec. 5, 1978. The inventors disclosed the use of a composition which includes a high molecular weight salt having a particular structural formula and molecular weight range.
A more specific type of lubricating composition in the form of a vaginal suppository is disclosed within U.S. Pat. No. 4,347,237, issued Aug. 31, 1982. The suppository is solid at room temperature and melts at body temperature due to its composition which includes a variety of different types of water soluble polyoxy alkaline polyol components.
As indicated above, the literature includes a number of disclosures of compositions and methods of applying those compositions to a substrate such as skin or mucous membranes in order to improve lubrication or relieve dryness. The effect is generally obtained by the application of a synthetic lubricant or a synthetic moisturizer and not by the inclusion of an active ingredient within the composition. However, U.S. Pat. No. 4,184,974, issued Jan. 22, 1980, to Leuven, discloses a lubricant composition which includes a topical biocidal agent. A similar type of composition containing such a biocidal agent is disclosed within U.S. Pat. No. 4,267,168, issued May 12, 1981.
The present invention is premised on the surprising discovery that the oil extracted from the Yerba Santa plant (Eriodictyon californicum; Eriodictyon glutinosum; also known as "consumptive's weed"; "bear's weed" "mountain balm" and "gum plant") is extremely effective in providing long-lasting relief of a variety of types of mild to severe dryness of internal mucosal membranes (specifically in the respiratory and gastrointestinal tracts), with no unpleasant side effects.
The Yerba Santa plant is an evergreen shrub indigenous to the hills and mountains of California and northern Mexico, and was long used by Indians for a number of purposes. See, e.g., A. R. Hutchens, Indian Herbalogy of North America, Ontario: Merco, 1975, at pp. 317-318. A number of references to the Yerba Santa plant teach its use as an expectorant (e.g., N. Coon, The Dictionary of Useful Plants, Emmaus, Pa.: Rodale Press, (1974)), in treating colds, sore throats, catarrh, stomach aches, vomiting and diarrhea (see A. R. Hutchens, supra), in treating hemorrhoids (D. G. Spoerke, Herbal Medications, Santa Barbara, Calif.: Woodbridge Press, 1980, at p. 183), in treating diseases of the lung (Los Remedios de la Gente: A Compilation of Traditional New Mexican Herbal Medicines and Their Use, compiled by M. Moore, 1977), and in masking the taste of quinine and other bitter medications (Spoerke, supra; see also G. E. Trease et al., Pharmacognosy, London: Cassell & Colber, 1978, at p. 463)).
In a book entitled "The Herb Book", first edition, Benedict Lust Publications, New York, 1974, it is indicated that American Indians smoked or chewed the leaves as a cure for asthma. They also used the leaves as a tea for colds and for a mouthwash preparation. Drying and smoking the leaves as well as boiling the leaves in water is disclosed in other publications such as The Herb Book wherein it is indicated that Yerba Santa is an excellent expectorant, valuable for colds, chronic laryngitis, bronchitis, lung problems and asthma.
A book entitled "Herbal Medications", by David G. Spoerke, Jr., published by Woodridge Press Publishing Company, Santa Barbara, Calif., 1980, discloses what appears to be the main use of the Yerba Santa extract which is to combine the extract with other substances in order to mask the bitter taste of a substance such as quinine. On page 183, the book specifically indicates that "The volatile oil has irritant properties that make it useful as an expectorant." The book also indicates that "The volatile oil could be irritating to the mucous membranes of the gastrointestinal tract if a large amount were taken."
In the book "Pharmacognosy (Eleventh Edition)", published by Bailliere Tindall, London, 1978, the eriodictyon fluid is described under the section entitled "Volatile Oils and Resins" and is again indicated as being a vehicle used for masking the taste of bitter and otherwise disagreeable medicines, particularly quinine.
Publications discussing the Yerba Santa plant include the Coon, Hutchens, Moore, Spoerke, and Trease et al. references, cited in the preceding section, as well as V. J. Vogel, American Indian Medicine, The University of Oklahoma Press, 1970, at pp. 83, 399-400; W. H. Lewis et al., Medical Botany: Plants Affecting Man's Health, New York: John Wiley & Sons, 1977, at p. 301; P. Huson, Mastering Herbalism: A Practical Guide, New York: Stein and Day, 1974, at p. 32; B. C. Harris, The Complete Herbal. Barre, Mass.: Barre Publishers, 1972, at p. 197; N. Coon, Using Plants for Healing, Hearthside Press, 1963, at p. 122; M. Grieve, A Modern Herbal. vol. 22, New York: Hafner Publishing Co., 1959, at p. 865; and V. E. Tyler et al., Pharmacognosy, Philadelphia: Lee & Febiger, 1981, at p. 148.
There are known possessing what is referred to as mucolytic activity on both purulent mucous and non-purulent mucous. Perhaps the most well known is N-acetylcysteine.
Because N-acetylcysteine has some undesirable properties, attempts have been made to develop new compounds. One such group of compounds is disclosed by Maltz in U.S. Pat. No. 4,409,138, issued Oct. 11, 1983. This patent discloses compounds which have topical mucolytic activity in particular on secretions of the respiratory passages. The compound are indicated as being particularly desirable in that they are not absorbed by the tissues which they come into contact with, but are able to reach the gastrointestinal tract unaltered, where they are metabolized to non-toxic products which can be completely eliminated from the body without undesirable side effects. Similar compounds are disclosed by Maltz within U.S. Pat. No. 4,559,322 issued Dec. 17, 1985.
Other compounds have been disclosed which act as inhibitors of mucous secretion. Such compounds are disclosed within U.S. Pat. No. 4,939,169 issued Jul. 3, 1990 to Bundy et al.
Mucolytic compounds have been known for some time as exemplified by Canadian Patent 821,525 issued Aug. 26, 1969. This patent discloses N-acetylcysteine compositions which include a variety of excipient materials along with the active ingredient of N-acetylcysteine. A number of other active ingredients may be combined with the N-acetylcysteine in order to obtain a desirable pharmacological effect. Mention is made of using suitable aerosol propellants.
Other mucolytic compounds which are formulated within aerosol and oral dosage forms are disclosed with European Patent Application 0,015,544 published Sep. 17, 1990.
Based on the above publications, it appears as though there is a considerable art disclosing eriodictyon fluid and some possible pharmaceutical uses. There is also art disclosing mucolytic compounds which can be placed in the form of aerosols or oral formulations. However, the invention disclosed herein relates to specific eriodictyon fluid formulations which are applied to internal mucosal membranes in order to promote the formation of mucous on internal membranes. The pharmaceutical formulations and methods of using such are described in detail below.